title: Purification and characterization of myxobacterial hemagglutinin, a development-specific lectin of Myxococcus xanthus.
abstract: Myxococcus xanthus is a Gram-negative bacterium that has a complex life cycle which includes cellular aggregation and sporulation. During the period of cellular aggregation, a lectin-like protein called myxobacterial hemagglutinin (MBHA) is synthesized. A four-step purification procedure for MBHA is described. It consists of chromatography on DEAE-cellulose, CM-cellulose, and hydroxyapatite, followed by gel filtration on Bio-Gel P-30. This procedure gives good yields of MBHA (40-50%) free of contaminating proteins. The purified protein has been partially characterized. It exists as a monomer in solution with an apparent Mr = 28,000 and an isoelectric point of 8.3. The amino acid composition of MBHA has been determined. It shows a very high content of glycine (19%) as well as aromatic amino acids (9%); it has a low percentage of charged amino acids. No detectable carbohydrate was found in a large sample (50 micrograms) of MBHA. The far-ultraviolet CD spectrum of MBHA indicates a secondary structure which contains very little alpha-helix, 50 +/- 10% beta-sheet, and 50 +/- 10% random coil. MBHA comprises 1-2% of soluble protein of M. xanthus at the time of cellular aggregation. The fact that it is a lectin suggests that it may play a role in cell-cell recognition or adhesion.
mesh_terms: D000596:Amino Acids / Q000032:analysis; D002449:Cell Aggregation; D002942:Circular Dichroism; D006384:Hemagglutination; D006388:Hemagglutinins / Q000302:isolation & purification*; D007106:Immune Sera; D005779:Immunodiffusion; D007700:Kinetics; D009231:Myxococcales / Q000276:immunology*; D011487:Protein Conformation
chemical_list: D000596:Amino Acids; D006388:Hemagglutinins; D007106:Immune Sera